What is claimed is:
1. A background noisespeech classification method comprising the steps of:
calculating power information and spectral information of an input signal as feature amounts; and
comparing the calculated feature amounts with estimated feature amounts constituted by estimated power information and estimated spectral information in a background noise period, thereby deciding whether the input signal belongs to speech or background noise.
2. A method according to claim 1, further comprising the step of updating the estimated feature amounts by different methods depending on whether it is decided that the input signal belongs to background noise or speech, and setting an update amount when it is decided that the input signal belongs to background noise to be smaller than an update amount to be set when it is decided that the input signal belongs to speech.
3. A method according to claim 1, further comprising the step of, when a decision result indicating that the input signal belongs to speech or background noise changes from speech to background noise, forcibly changing the decision result to speech for a specific period, and changing the specific period by using the estimated power information and estimated spectral information in the background noise period.
4. A background noisespeech classification method comprising the steps of:
calculating power information and spectral information of an input signal as feature amounts;
comparing the calculated feature amounts with estimated feature amounts constituted by estimated power information and estimated spectral information in a background noise period, thereby analyzing power and spectral fluctuation amounts; and
when a result obtained by analyzing the power and spectral fluctuation amounts indicates background noise, deciding that the input signal belongs to background noise, and otherwise, deciding that the input signal belongs to speech.
5. A method according to claim 4, further comprising the step of updating the estimated feature amounts by different methods depending on whether it is decided that the input signal belongs to background noise or speech, and setting an update amount when it is decided that the input signal belongs to background noise to be smaller than an update amount to be set when it is decided that the input signal belongs to speech.
6. A method according to claim 4, further comprising the step of analyzing the spectral fluctuation amount by comparing a predetermined threshold with a distortion value between a spectral envelope obtained from the spectral information of the input signal and a spectral envelope obtained from the estimated spectral information in the background noise period.
7. A method according to claim 4, further comprising the step of analyzing the spectral fluctuation amount by comparing a predetermined threshold with a distortion value between a spectral envelope obtained from the spectral information of the input signal and a spectral envelope obtained from the estimated spectral information in the background noise period, and also changing the threshold in accordance with the estimated power information.
8. A method according to claim 4, further comprising the step of, when a decision result indicating that the input signal belong to speech or background noise changes from speech to background noise, forcibly changing the decision result to speech for a specific period, and also changing the specific period in accordance with the estimated power information and estimated spectral information in the background noise period.
9. A voicedunvoiced classification method comprising the steps of:
preparing a voiced appearance probability table and an unvoiced appearance probability table in which voiced and unvoiced appearance probabilities are respectively written in correspondence with speech feature amounts;
obtaining voiced and unvoiced probabilities by referring to said voiced appearance probability table and said unvoiced appearance probability table by using a feature amount calculated from input speech as a key; and
deciding on the basis of the voiced and unvoiced probabilities whether the input speech belongs to voice or unvoice.
10. A background noise decoding method comprising the steps of:
extracting a decoded excitation signal parameter, a gain
decoded parameter, and a decoded synthesis filter parameter from decoded parameters obtained by decoding encoded data;
decoding an excitation signal and a gain from the decoded excitation signal parameter and the gain decoded parameter;
smoothing the gain such that the gain changes smoothly; and
generating a synthesized signal by using a signal obtained by multiplying the excitation signal by the smoothed gain and synthesis filter characteristic information based on the decoded synthesis filter parameter.
11. A method according to claim 10, wherein the step of smoothing the gain comprises gradually increasing the gain when the gain increases, and quickly decreasing the gain when the gain decreases.
12. A speech encoding method comprising the steps of:
dividing an input speech signal into frames each having a predetermined length;
obtaining a pitch period of a future frame with respect to a current frame to be encoded; and
encoding the pitch period.
13. A speech encoding method comprising the steps of:
dividing an input speech signal into frames each having a predetermined length, and further dividing a speech signal of each frame into subframes;
obtaining a predictive pitch period of a subframe in a current frame by using pitch periods of at least two frames of the current frame to be encoded and past and future frames with respect to the current frame; and
obtaining a pitch period of a subframe in the current frame by using the predicted pitch period.
14. A method according to claim 13, further comprising the step of encoding the pitch period of the subframe in the current frame.
15. A method according to claim 13, further comprising the step of preparing a pitch filter for suppressing or emphasizing a pitch period component of an input speech signal, and determining a transfer function for said pitch filter by using the pitch period of the subframe in the current frame.
16. A speech encoding method comprising the steps of:
preparing an adaptive codebook storing a plurality of adaptive vectors generated by repeating a past excitation signal series at a period included in a predetermined range;
dividing an input speech signal into frames each having a predetermined length, and further dividing a speech signal of each frame into subframes;
obtaining a predicted pitch period of a subframe in a current frame by using pitch periods of at least two frames of the current frame to be encoded and past and future frames with respect to the current frame; and
determining a search range for subframes in the current frame by using the predicted pitch period to select an adaptive vector with a period that minimizes an error between a target vector and a signal obtained by filtering an adaptive vector extracted from said adaptive codebook through a perceptually weighted synthesis filter.
17. A method according to claim 13, wherein the step of obtaining the pitch period of the frame comprises adaptively deciding a pitch period analysis position for each frame.
18. A method according to claim 13, further comprising the step of selecting a method of obtaining a pitch period of a subframe in the current frame in accordance with continuity of pitch periods.
19. A method according to claim 13, further comprising the steps of:
preparing a relative pitch pattern codebook storing a plurality of relative pitch patterns representing fluctuations in pitch periods of a plurality of subframes; and
expressing a change in pitch period of plural subframes with one relative pitch pattern selected from said relative pitch pattern codebook.
20. A speech encoding apparatus comprising:
means for dividing an input speech signal into frames each having a predetermined length;
means for obtaining a pitch period of a future frame with respect to a current frame to be encoded; and
means for encoding the pitch period obtained by said means for obtaining the pitch period.
21. A speech encoding apparatus comprising:
a divider section for dividing an input speech signal into frames each having a predetermined length, and further dividing a speech signal of each frame into subframes;
a predicted subframe pitch period calculation section for obtaining a predicted pitch period of a subframe in a current frame by using pitch periods; of at least two frames of the current frame to be encoded and past and future frames with respect to the current frame; and
a subframe pitch period calculation section for obtaining a pitch period of a subframe in the current frame by using the predicted pitch period.
22. A speech encoding apparatus comprising:
an adaptive codebook storing a plurality of adaptive vectors generated by repeating a past excitation signal series at a period included in a predetermined range;
a divider section for dividing an input speech signal into frames each having a predetermined length, and further dividing a speech signal of each frame into subframes;
a predicted subframe pitch period calculation section for obtaining a predictive pitch period of a subframe in a current frame by using pitch periods of at least two frames of the current frame to be encoded and past and future frames with respect to the current frame; and
a search range determination section for determining a search range for subframes in the current frame by using the predicted pitch period to select an adaptive vector with a period that minimizes an error between a target vector and a signal obtained by filtering an adaptive vector extracted from said adaptive codebook through a perceptually weighted synthesis filter.
23. A recording medium on which a program is recorded, said program being used to execute processing of dividing an input speech signal into frames each having a predetermined length, and obtaining a pitch period of a future frame with respect to a current frame to be encoded, and processing of encoding the pitch period.
24. A recording medium on which a program is recorded, said program being used to execute processing of dividing an input speech signal into frames each having a predetermined length, further dividing a speech signal of each frame into subframes, and obtaining a predicted pitch period of a subframe in a current frame by using pitch periods of at least two frames of the current frame to be encoded and past and future frames with respect to the current frame, and processing of obtaining a pitch period of a subframe in the current frame by using the predicted pitch period.
25. A computer-readable recording medium on which a program for performing speech encoding processing is recorded, the program being used to execute processing of dividing an input speech signal into frames each having a predetermined length, further dividing a speech signal of each frame into subframes, and obtaining a predicted pitch period of a subframe in a current frame by using pitch periods of at least two frames of the current frame to be encoded and past and future frames with respect to the current frame, and processing of determining a search range for subframes in the current frame by using the predicted pitch period to select an adaptive vector with a period that minimizes an error between a target vector and a signal obtained by filtering an adaptive vector extracted from an adaptive codebook through a perceptually weighted synthesis filter, said adaptive codebook storing a plurality of adaptive vectors generated by repeating a past excitation signal series at a period included in a predetermined range.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
We claim the following:
1. A method to provide indirect evaporative cooling while controlling humidity of the cooled product air by having three plates in parallel:
a) forming a first space and second space between adjacent plates with the middle plate being a common plate to both spaces;
b) wetting opposing surfaces of the adjacent plates;
c) keeping some surface areas of opposing surfaces dry
d) passing air in the first space in two types of channels, working channels and product channels;
e) passing air in the second space in working channels and product channels in cross flow to the flow in the first space channels;
f) controlling the humidity in the product channels by the amount of wet surfaces the product air is exposed to in the product channels; and
g) cooling the air in the product channels by the dry surfaces being cooled by heat transfer across the common plate in this area and the evaporation cooling on the opposite surface of the common plate in the adjoining space that is occurring in a wet area of a working channel.
2. The method of claim 1 wherein pre-cooling occurs in each space in a section where working channels are on both sides of the common plate having dry areas and wet areas having equal area. The pre-cooling section having the dry area occurring first in the working channel having the transitive to a wet area occurring on a diagonal to the direction of flow in the working channel having the orientation of the working channel dry area in a first spacing being opposite from the dry area of the working channel of the second space such that the common plate dry area in the first space is opposite the wet area of the common plate in the second space pre-cooling of the working air in the second space by heat transfer from the first space and pre-cooling of the working air in the first space by heat transfer from the second space.
3. A method according to claim 1 wherein after the product fluid, for example air, has passed through the product cooling section it passes over a wet surface.
4. A method according to claims 1-2 wherein the product fluid may have it’s own pump, fan or any fluid moving device.
5. A method according to claims 1-3 wherein the working air is heated before entering the pre-cooling section.
6. A method according to claim 1 wherein the humid working air exhaust becomes the product and is directed to the user for humidification of desired area.
7. A method according to claim 1 wherein outside ventilation air is used as the product fluid for the user in, for example, a conditioned space and is passed through a solid or liquid desiccant dehumidifier; this product air is then cooled by passing its two streams over the dry side of two product cooling sections, and then is directed to the user; simultaneously the exhaust air from conditioned space andor outside air that has passed through a solid or liquid desiccant dehumidifier is used as the working air, that then passes by two streams through the pre-cooling section, is then directed straight across the product cooling section and then is exhausted out.
8. A method according to claim 1 wherein all or a portion of the inside recirculation air is used as a product fluid for the user in, for example, a conditioned space and is passed through a solid or liquid desiccant dehumidifier; this product air is cooled by passing its two streams over the dry side of two product cooling sections and then is directed to the user; simultaneously outside air and in some cases all or a portion of the same recirculation air from conditioned space, after its passing through the desiccant dehumidifier, is used as the working air, that then passes by two streams through the precooling section, is directed straight across the product cooling section and then is exhausted out.
9. An apparatus for indirect evaporative cooling comprised of at least two plates in parallel, each plate having two surfaces wherein:
a) at least part of one of the surfaces is impermeable to the fluid used for evaporation,
b) the plates are made of a material that has a wick like capability that transports the liquid used for evaporation to the areas of the plates where evaporation is to occur and once there allows the liquid to evaporate,
c) the impermeable areas are thin so as to allow for heat transfer,
d) the opposing surfaces of adjoining plates are of like surface permeability,
e) the evaporation occurs in the areas without the impermeable surface and cools the surface and the working air,
f) the cooler temperatures due to the evaporation is in heat transfer contact with the impermeable surface and the product air that is in contact with this surface. The apparatus of claim 1, has channel guides, working air channels, and product air channels to direct the flow in a desired path.
10. The apparatus of claim 2 where the shape is of a diamond.
11. The apparatus of claim 2, where the shape is square.
12. The apparatus of claim 1 where the impermeable surface is created by a plastic coating on the wick material.
13. The apparatus of claim 1 where the plates of the stack have impermeable surfaces on the product channels to inhibit any direct evaporation occurring.
14. The apparatus of claim 1 where the working channel have some areas of impermeable surface.
15. The apparatus of claim 1 where the shape has one part removed.
16. The apparatus of claim 1 where the shape uses the forth quadrant to have direct evaporative cooling of the product air after it has been cooled by the indirect cooling.
17. The apparatus of claim 1 where the plates are fed the liquid for evaporation by feeder wicks.
18. The apparatus of claim 1 where the plates are sloped with the lower edge fed liquid for evaporation by a reservoir.
19. The apparatus of claim 1 where the working air is heated before it is used in the working air channels.
20. The apparatus of claim 1 where the working air is dehumidified before it is used in the working air channels.
21. The apparatus of claim 1 where flow of working air and product air between adjoining channels separated by a plate are in cross flow.
22. The apparatus of claim 1 where flow of working air and product air between adjoining channels separated by a plate are more counterflow.
23. The apparatus of claim 1 where the working air is taken from the exhaust after the product air was used.
24. The apparatus of claim 1 where the some working air exhaust is added to the product air to accomplish the desired temperature and humidity.
25. An apparatus of claim 2 wherein:
a) one of the quadrants with only working air channels has one half of each quadrant surface covered with plastic, such that the working air enters one channel;
b) the channel is in the non evaporative portion of the channel and gets precooled by adjacent layers;
c) the working air channels also in the quadrant that have evaporative cooling in area of their channels; and
d) the channels interface with the first channel plastic surface.
26. A method to provide indirect evaporative cooling and to control the humidity by having at least two plates with two surfaces wherein there is:
a) wetting on opposing surfaces of the plates;
b) keeping some surfaces areas of the opposing surfaces dry;
c) passing air between the plates;
d) controlling the humidity by varying the amount of wet surfaces to which the air is exposed; and
e) cooling the air over the dry areas by heat transfer by having evaporation occurring on the opposite side of each plate in the area.